Magnetic iron alloy



Patented Jan. 5, 1937 I UNITED .STATES' PATENT caries 2.000.911 momma-mom my Robert A. Curry, Chicago, 111., assignor, by meaneassignments, to Indiana Steel Products Co pany, Chicago. Ill., a corporation of Indiana No Drawing.

Application March 29, 1935. Serial No. 13,070

3 Claims. (Cl. 75-123) It has heretofore been known (Ruder Patent No. 1,947,274) to cast alloy permanent magnets consisting of iron, nickel and aluminum. I have now found that an alloy of iron, nickel, and beryllium, with or without a small percentage of cobalt, possesses even more deslrableproperties than the previously known alloy of iron, nickel and aluminum.-

It is therefore one of the important objects of this invention to provide an alloy consisting essentially of nickel, beryllium and iron, with or without a small percentage of cobalt, having permanent magnetic properties and also good resistance to heat and corrosion.

Other and further important objects of this invention will become apparent from the following description and appended claims.

v The alloy of my invention has the following general composition, percentages being expressed as percentage by weight:

,Nickel 15 to 25% Beryllium 0.25 to 15% Cobalt to Iron Balance It is to be understood that small traces of impurities and of metallic and solid non-metallic substances other than those in the foregoing formula may be present. However, my alloy consists essentially of nickel, beryllium and iron, with a small optional percentage of cobalt to give ductility and desirable magnetic properties.

A preferred formula is as follows:

Nickel ..about 20% Beryllium 6 to Cobalt 3 to 5% Iron Balance It is also possible to omit the cobalt entirely. with some sacrifice in ductility and in its masnetic properties. A satisfactory formula, omitting cobalt, is as follows:

Nickel about 5 Beryllium 0.25 to 6% Iron -1 Balance Any of the alloys coming within the proportions indicated in the above formula will be 0 found to have age-hardening properties, and consequently need not be heat treated, although a heat treatment is not excluded from the scope of my invention. Y

The magnetic properties of a cast alloy of my invention will depend in part upon the size of the casting. As illustrative of the magnetic properties possessed by my alloy, a bar of an alloy consisting of about 20% of nickel, 12% beryllium, 3 to 5% cobalt and the balance of iron,- shows a coercive force varying from about 470 to 550 Gilberts per centimeter, and a residual varyingfrom about 8750 to 10,000 Gauss.

A bar formed from an alloy consisting of about 20% nickel, 6% beryllium and the balance iron has a coercive force varying from about 425 to 475 Gilberts per centimeter and a residual varying from about 7500 to 8500 Gauss.

I am aware that numerous details of the process may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted, hereon otherwise than necessitated by the prior art. if

I claim as my invention: a

1. A magnetic iron alloy consisting essentially of about 20% nickel, 12% beryllium, 3 to 5% cobalt and the balance iron.

2. A permanent magnet consisting essentially of about 20% nickel, 6 to 15% beryllium, 3 to 40 5% cobalt and the balance iron. I

3. A magnetic iron alloy consisting essentially of from 15 to 25% nickel, 6 to 15% beryllium, 3 to 5% cobalt and the balance iron.

ROBERT A. 

